![]() ![]() For Nehalem and later CPU families, the accuracy was improved and should be cca +-5 ☌ uniform across the whole temperature range. At temperatures below 50 ☌ the reading is not guaranteed to be functional and can't provide a meaningful temperature value (should be considered to indicate only a temperature < 50 ☌ and not a specific value). ![]() For these families the precision is in best case -3/+7 ☌ (or up-to -5/+10 ☌) at Tj,max and gets even worser at temperatures ~50 ☌, where the accuracy degrades to +-10☌ (up-to -10/+15☌). Again, the situation depends whether the CPU belongs to the pre-Nehalem family. At lower temperatures (higher distance to Tj,max), the accuracy gets worser and at some point (~ 50 ☌ usually) saturation occurs and values read below this point are highly inaccurate (practicaly cannot be used to provide a true temperature). It seems that older DTS implementations have been designed to catch the hottest temperature only (to engage throttling when overheated), so the sensor returns more precise data only at temperatures close to Tj,max. The second problem (which many users don't seem to realise) is the accuracy of the DTS sensor. For Nehalem and later CPUs, the Tj,max value can be read from an internal CPU register, so this issue should be resolved. So in many cases for pre-Nehalem CPUs, to determine the correct Tj,max value is just a pure guessing. However those CPUs can have different Tj,max set even for same models (determined during manufacturing). Various people have performed extensive experiments to determine more accurate values. Although Intel has published some fixed numbers for certain CPU families, it has been proven that many of them are not correct. And this is the first problem, since for pre-Nehalem CPUs (like Core2, Atom, etc), the precise value cannot be read from any register (there are some partial methods but don't seem to be reliable on all models). ![]() Thus to report a correct temperature, the Tj,max needs to be known. Since many users are confused about certain values measured, there is a clarification needed.įirst, the value read from the DTS is not an absolute values in degrees Celsius, but it's an offset (distance) from the maximum CPU junction temperature ( Tj,max). Later Intel CPUs feature a Digital Thermal Sensor (DTS) which measures the temperature for each core. ![]()
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